(1) Field of the Invention
The invention described herein relates to the field of sonar arrays and more particularly to the mounting of elements to reduce or prevent cavitation.
(2) Description of the Prior Art
The interaction between adjacent transducers can produce cavitation due to acoustic effects alone. Low-frequency Class IV flextensional transducers are often placed in arrays in very close proximity. In some cases, adjacent surfaces are within a few inches of each other. Ideally, such transducers should be spaced one-half wavelength of the acoustic waves apart in order to minimize acoustic interactions between transducers. However, system constraints often make this impossible. For example, an array of such transducers is often towed in a VDS (variable depth sonar) type towed body. It is desirable to make such a body as small as possible for several other reasons. For example, handling problems (during development and retrieval) are minimized. Also, snap loads become a problem as the body gets larger in size. Finally, the drag force on the towed body is increased, which then requires more downward force (in the form of weight or negative lift) to maintain the array at the required depth. The result of the close transducer spacing is that cavitation can occur, which can distort the acoustic signal, reduce the signal strength, and cause damage to the face of the transducers. There is thus a need for a practiced solution to reduce cavitation within the constraints of the design for the towed sonar array.